945 research outputs found
Relativistic Kinetic Equations for Finite Domains and Freeze-out Problem
The relativistic kinetic equations for the two domains separated by the
hypersurface with both space- and time-like parts are derived. The particle
exchange between the domains separated by the time-like boundaries generates
source terms and modifies the collision term of the kinetic equation. The
correct hydrodynamic equations for the ``hydro+cascade'' models are obtained
and their differences from existing freeze-out models of the hadronic matter
are discussed
Physical mechanism of the (tri)critical point generation
We discuss some ideas resulting from a phenomenological relation recently
declared between the tension of string connecting the static quark-antiquark
pair and surface tension of corresponding cylindrical bag. This relation
analysis leads to the temperature of vanishing surface tension coefficient of
the QGP bags at zero baryonic charge density as T_\sigma = 152.9 +- 4.5 MeV. We
develop the view point that this temperature value is not a fortuitous
coincidence with the temperature of (partial) chiral symmetry restoration as
seen in the lattice QCD simulations. Besides, we argue that T_\sigma defines
the QCD (tri)critical endpoint temperature and claim that a negative value of
surface tension coefficient recently discovered is not a sole result, but
should also exist in ordinary liquids at the supercritical temperatures.Comment: Talk given at the Conference "Critical Point and Onset of
Deconfinement (CPOD)" that held on August 23 - 29, 2010, JINR, Dubna, Russia.
Contains minimal change
Particle Freeze-out and Discontinuities in Relativistic Hydrodynamics
Freeze-out of particles in relativistic hydrodynamics is considered across a
3-dimensional space-time hypersurface. The conservation laws for time-like
parts of the freeze-out hypersurface require different values of temperature,
baryonic chemical potential and flow velocity in the fluid and in the final
particle spectra. We analyze this freeze-out discontinuity and its connection
to the shock-wave phenomena in relativistic hydrodynamics.Comment: 6 figure
Exactly Solvable Model for the QCD Tricritcal Endpoint
An inclusion of temperature and chemical potential dependent surface tension
into the gas of quark-gluon bags model resolves a long standing problem of a
unified description of the first and second order phase transition with the
cross-over. The suggested model has an exact analytical solution and allows one
to rigorously study the vicinity of the critical endpoint of the deconfinement
phase transition. It is found that at the curve of a zero surface tension
coefficient there must exist the surface induced phase tranition of the 2-nd or
higher order. The present model predicts that the critical endpoint (CEP) of
quantum chromodynamics is the tricritical endpoint.Comment: 14 pages, 3 figures, invited talk given at the International Workshop
``Relativistic Nuclear Physics: from Nuclotron to LHC Energies'', Kiev,
Ukraine, June 18-22, 200
Analytical description of muon distributions at large depths
The analytical expression for integral energy spectra and zenith angle
distributions of atmospheric muons at large depths is derived. Fluctuations of
muon energy losses are described using the parametrized correction factor. The
fitting formula for the sea level muon spectrum at different zenith angles for
spherical atmosphere is proposed. The concrete calculations for pure water are
presented.Comment: Contribution to the 27th ICRC (Hamburg, August 7-15, 2001), 4 pages,
3 .eps figures, uses icrc.cl
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